Effect of Sodium Metabisulfite Soaking and Osmotic Dehydration Pre-Treatments on Physicochemical Characteristics of Dried Red Chili Pepper (Capsicum annuum L.)

Department of Food Science and Technology, Faculty of Agriculture, Universitas Sebelas Maret, Surakarta, Central Java, Indonesia

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Abstract

Red chili peppers, being a valuable horticultural product, are easily affected by biochemical and microbial spoilage and thus demand practical and economical post-harvest treatments. There has been no research specifically investigating the combination of sodium metabisulfite soaking and osmotic dehydration treatments. This study presents the first comprehensive report on the synergistic effect of combining sodium metabisulfite soaking and osmotic dehydration for preserving the quality of dried red chili. Using a completely randomized design, the research assessed physical parameters (yield, weight loss, texture, color) and chemical attributes (moisture content, antioxidant activity, vitamin C, sulfite residue) across varying sodium metabisulfite concentrations and osmotic dehydration levels. Results demonstrated that pre-treatments significantly (p < 0.05) improved physical characteristics, with notable increases in texture and color parameters and reductions in weight. Chemically, antioxidant activity significantly (p < 0.05) increased by 9.53%-24.79%, while vitamin C levels decreased by 12.86%-35.73%. Sulfite residue and moisture content decreased notably post-treatment. The optimal treatment identified was soaking in 0.30% sodium metabisulfite followed by osmotic dehydration in 70°Brix sucrose solution, offering the best balance between quality preservation and chemical residual safety. This approach provides a practical method for maintaining red chili quality during drying, enhancing its post-harvest value.